Yeah, I am also doubtful about the timeline of events. We have to look at the fact, that initially Wuhan doctors mention 27 cases of pneumonia of unknown origin at December 31st. But once there was declared that they have something, a lot of new cases got reported. And I see why. Doctors don't always try to see the actual reason for a pneumonia. A lot of infectious diseases cause pneumonia. So if a doctor sees pneumonia it gets treated without always asking for the cause. But if they know a new disease is spreading, all the strange cases suddenly can fit in a box.
So if there was early spread outside of China, would doctors have noticed a cluster of pneumonia cases? Maybe not. Each hospital may have one or two unexplained case, only in communication it gets a picture. So I don't think it is completely outlandish to think that the disease spread outside of Wuhan or China as early as late last year and was undetected as a new disease.
Yep it was also confirmed in sewage samples from December 2019 in Italy, but not yet that early in Canada. Before that stories circulated from military athletes tht got sick during and after the Wuhan military games. It's very possible that's how it initially seeded itself across the world.